The present invention relates to an X-ray imaging diagnostic apparatus emitting a low X-ray radiation dose and, more particularly, to an X-ray imaging diagnostic apparatus in which an X-ray radiation dose from an X-ray generating source for diagnosing dental disease or the like is less than 2/100 of an X-ray radiation dose required for conventional X-ray radiographs using a photo film. An X-ray image of an object is focused into an image by a fluorescent screen which is arranged in front of an optical system so that the image can be photographed and recorded by a high sensitivity imaging device or observed on a monitor or the like.
At present, the X-ray diagnosis for dental disease is performed by radiographing directly on high sensitivity X-ray film inserted into an oral cavity. This method is frequently used in Japan and an approximation of the total number of pictures taken in 1974 is 89,000,000. The X-ray radiation dose required for radiographing a molar region of an adult is 310 mrad per radiograph. This value is larger than the radiation dose of about 60 mrad which is absorbed by a subject in the case of a chest radiograph. Even though conventional radiographing systems have been partially improved to reduce that radiation dose, it still remains much higher than is desirable.
While the use of a television system having an image amplifier has spread recently in clinics and the X-ray exposure does is extremely decreased with the system at the time of diagnostic fluoroscopy, conventional radiography and development techniques are still used for the purpose of high accuracy information confirmation.